The present invention relates to vehicles that are propelled by air-thrusting mechanisms and, more particularly, to a flat-bottomed light boat with a fan propeller designed for flotation in shallow waters. This invention also pertains to a propulsion unit that moves the air-thrust vehicle.
Air-thrusting water craft serve unique purposes along water courses that are difficult to navigate by standard water vehicles. In swamps and other shallow waterways, such as exist in Florida and Louisiana, grasses and underwater vegetation make navigation in conventional water craft hazardous and difficult. One of the disadvantages of using boats with outboard motors is that they use the same trail numerous times; every time they pass it is easier and less resistance, but it damages the root structure of the vegetation growing in the mud. The current churns up the mud, loosens it up and more of it will wash out when the tide goes out. The air-thrusting mechanism of the air boat eliminates the need for water guided rudders, centerboards, and water propulsion impellers.
The engine and propeller of an air boat are typically enclosed in a protective metal cage that prevents objects, e.g., tree limbs, branches, user's clothing or wildlife from coming in contact with the whirling propeller, which could cause devastating damage to the vessel and traumatic injury to the operator and passengers. The propeller produces a rearward column of air that propels the airboat forward. Steering is accomplished by forced air passing across vertical rudders. There must be a forceful airflow in order for the vessel to be steered. Airboats do not have brakes; they cannot travel in reverse.
The characteristic flat-bottomed design of the airboat, in conjunction with the fact that there are no operating parts below the waterline permit the vessel to be easily navigated through shallow swamps, marshes, lakes and rivers. Airboats vary in size from 10-foot hunt/trail boats, with a two- to three-passenger capacity, to large 18-passenger and greater tour boats.
In recent years airboats have grown in popularity in the area of public safety. Airboats have proven to be indispensable for flood, shallow water and ice rescue operations. During the flooding of New Orleans following Hurricane Katrina in August of 2005, airboats from across the United States rescued thousands of flood victims. Thirty airboats evacuated over 3,000 patients and medical staff from four downtown New Orleans hospitals in less than 36 hours. The advantages, capabilities and benefits of using airboats for water rescue operations have been described in various articles. As a consequence, despite the limitations in steering of the air boats, the benefits of the air-propelled watercraft account for increase in this type of vehicle in a variety of industries.
Another attractive use of the air boats is for tourism industry. The original airboats were built tall, which allowed passengers a wide view of the area. The smaller airboats cannot run through grass of that height. Because of the lower horsepower used by smaller boat engines they cannot travel through the same areas.
Airboats are powered by either an aircraft or large block automotive engine, ranging from 125 to over 600 horsepower. Replacement parts and ease of repair make the automotive engine the preferred power source. Also, high octane automotive gas is less expensive than aviation gas required by the aircraft engines. An automotive engine powered airboat generally has more power to push through high grass or carry heavy loads. An aircraft engine powered airboat may still be preferred in situations where a light boat or greater maneuverability is desired.
The factory-built air boats are relatively expensive. However, the advantages afforded by the air-thrust motor can be made available for other boats that use conventional outboard motors. The outboard motors can be usually easily dismounted from the boat for storage or repair. The present invention contemplates provision of a mounting assembly for an air-thrust motor that can be mounted on a conventional boat in place of an outboard motor and make the modified watercraft for operation in shallow water, swamps and marshes.